Patent GB-817453-A (GB)
Title: Improvements in or relating to screw operated mechanisms
Inventor: HUNTER GEORGE WILLIAM
IPC: B23G1/04
Filed: 1957-09-13
Abstract: 817,453. Linkwork. STANDARD TELEPHONES & CABLES Ltd. Sept. 13, 1957, No. 28910/57. Class 80 (3). [Also in Group XXII] In a mechanism for controlling linear speed, applied to the feed of a bracket 15 along a main slide 1 in a machine which may be used for thread-cutting, a feed screw 10 is adjustably inclined to the slide 1 and the movement of a saddle 8 carrying the feed screw nut is resolved into two components, one along the slide 1 and the other along slides 5 perpendicular to the slide 1. The values of the two components, and hence the speed of the bracket 15, are controlled by adjustment of the inclination of the feedscrew 10. The screw 10 is rotatable in a saddle slide 9 which is adjustable, along a quadrant 13, about the apex of the bevel gearing (not shown) driving the screw from a shaft 20. The saddle 8 is spigoted to a block 7 slidable on the transverse slides 5. The slides 5 are supported by the bracket 15 and a bracket 6 slidable on a second main slide 1. A headstock spindle 19 is driven through bevel or screw gearing by the shaft 20 driving the screw 10. The bracket 15 is T-slotted to carry accessories such as a slide rest. In use the saddle slide 9 is angularly adjusted along the graduated quadrant 13 to give the required speed of the bracket 15 relative to the spindle 19, i.e. the required threads per inch, a fine adjusting screw (not shown) being provided on the slide. The slide 9 is then clamped by bolts 14 and means 37, and the spigot connection, Fig. 3 (not shown) between the saddle 8 and block 7 is also clamped. In order to check the setting of the slide 9 a dial indicator is clamped to the bracket 15 with its plunger against a setting stop on the headstock 18. A lever 22 is actuated to move a microswitch (not shown) into contact with a cam (not shown) on the spindle 19, the microswitch controlling a pulse counter 23 which thus counts the revolutions of the spindle 19. The machine is then run until the required threads per inch are indicated on the counter 23, when the dial indicator may be checked for travel and the spindle position be checked by the insertion of a removable pin. The counter 23 may also be used as a machine cut-out, or for measuring linear displacement. A T-slotted bed slide 25 carries accessories such as a tailstock. The headscrew nut carried by the saddle 8 may be of phosphor bronze or a plastic such as polytetrafluorethylene and may be whole or split. A nut-disengaging lever and a hand wheel 12 are provided for manual tra. verse. The slides 1, 5 are adjustable in their mountings. The machine shown may also be used for winding the frame grids of thermionic valves, in which case the bracket 15 carries wire tensioners or guides and the bed slide 25 carries a double winding head, Fig. 6. The winding head comprises two collets 41, 42 to carry the grid frames, and an operating lever 43 which can be moved to clutch one or other of the collets to a shaft 46 which is driven by the headstock spindle 19. Movement of the lever 43 also reverses the machine motor so that alternate use of the collets 41, 42 causes the bracket 15, Fig. 1, alternately to move to the right and to the left. Thus one grid can be wound in one collet while the operator is loading the other, stationary, collet.